Inductance element and manufacturing method thereof

Abstract

The invention provides an inductance element and a manufacturing method thereof. The inductance element comprises a magnet, a coil and an end electrode. The coil is embedded in the magnet, and the end electrode is exposed out of the magnet and electrically connected with the coil. The coil comprises a plurality of internal conductor layers which are arranged in the axial direction of the coil and are connected in series, and every two adjacent internal conductor layers are electrically connected through a connecting conductor; in every two adjacent internal conductor layers, the surface, away from the corresponding connecting conductor, of one internal conductor layer is provided with a concave part, and the concave part and the corresponding connecting conductor are oppositely arranged in the thickness direction of the internal conductor layer. The inductance element can effectively prevent short circuit of the upper internal conductor layer and the lower internal conductor layer caused by the protrusion of the connecting conductor in the pressing process of the magnet material, so as to improve the electrical qualified rate of products.

Description

Technical Field

[0001] The present invention relates to the field of power devices, and in particular to an inductor element and a manufacturing method thereof. Background Art

[0002] In one-piece molded inductor products, since the magnetic part needs to be pressed and formed, the connection points of some internal conductor layers are relatively thick. Due to the uneven surface, the insulating medium layer will be punctured, and the thickness will cause a short circuit between layers, resulting in the scrapping of the inductor component product. Summary of the invention

[0003] The first object of the present invention is to provide an inductor component that can effectively prevent the upper and lower internal conductor layers from being short-circuited due to the protrusion of the connecting conductor during the pressing process of the magnetic material, so as to improve the electrical qualification rate of the product.

[0004] The second object of the present invention is to provide a method for manufacturing an inductor element that can effectively prevent the short circuit between the upper and lower internal conductor layers caused by the protrusion of the connecting conductor during the pressing process of the magnetic material, so as to improve the electrical qualification rate of the product.

[0005] The third object of the present invention is to provide an inductor element manufactured by the above manufacturing method.

[0006] To achieve the above-mentioned first purpose, the present invention provides an inductor element, including a magnet, a coil and an end electrode; the coil is buried in the magnet, and the end electrode is exposed to the magnet and electrically connected to the coil; the coil includes a plurality of internal conductor layers arranged along the axial direction of the coil and connected in series, and two adjacent internal conductor layers are electrically connected through a connecting conductor; among the two adjacent internal conductor layers, a recessed portion is provided on the surface of one of the internal conductor layers away from the corresponding connecting conductor, and the recessed portion and the corresponding connecting conductor are arranged relative to each other in the thickness direction of the internal conductor layer.

[0007] It can be seen from the above scheme that the relative surface of the internal conductor layer and the corresponding connecting conductor in the thickness direction is lower than the surface of the connecting conductor. In this way, during the pressing process of the magnetic material, space can be reserved for the deformation of the connecting conductor, thereby preventing the connecting conductor from bulging upward after being subjected to force and short-circuiting with the adjacent internal conductor layer, thereby improving the product qualification rate.

[0008] A preferred solution is that the depth of the recessed portion is less than 1 / 3 of the thickness of the internal conductor layer where the recessed portion is located.

[0009] A preferred solution is that the cross-sectional area of ​​the recessed portion is smaller than the cross-sectional area of ​​the connecting conductor corresponding to the recessed portion.

[0010] It can be seen that by controlling the depth and cross-sectional area of ​​the recessed portion, the increase in DC resistance can be controlled within 5% while avoiding a short circuit in the internal conductor layer, and the inductance of the product is not affected.

[0011] A preferred solution is that the inductor element further includes an insulating dielectric coating layer, the insulating dielectric coating layer is coated outside the coil, and the coil and the magnet are electrically insulated by the insulating dielectric coating layer.

[0012] It can be seen that the insulating medium coating layer is provided to achieve electrical insulation between the coil and the magnet.

[0013] To achieve the above second objective, the present invention provides a method for manufacturing an inductor element, the manufacturing method comprising: step 1, forming a metal film layer on an insulating dielectric layer, arranging a photoresist layer on the metal film layer, and forming an electrode groove on the photoresist layer; step 2, after arranging an internal conductor layer in the electrode groove, removing the photoresist layer and the metal film layer to complete the manufacturing of a single internal conductor layer; step 3, arranging an insulating dielectric layer on the formed internal conductor layer, and after the insulating dielectric layer is solidified, opening a through hole at a preset position of the insulating dielectric layer; step 4, forming a metal film layer on the insulating dielectric layer after the hole is opened, arranging a photoresist layer on the metal film layer, and forming an electrode groove on the photoresist layer, the electrode groove passes through the through hole and extends to the internal conductor layer of the lower layer or extends to the metal film layer; step 5, after arranging the internal conductor layer in the electrode groove formed in step 4, removing the photoresist layer and the metal film layer to complete the manufacturing of the next internal conductor layer, the upper surface of the internal conductor layer is recessed downward at a position relative to the through hole, and a connecting conductor connecting two adjacent internal conductor layers is formed in the through hole.

[0014] It can be seen from the above scheme that the relative surface of the internal conductor layer and the corresponding connecting conductor in the thickness direction is lower than the surface of the connecting conductor. In this way, during the pressing process of the magnetic material, space can be reserved for the deformation of the connecting conductor, thereby preventing the connecting conductor from bulging upward after being subjected to force and short-circuiting with the adjacent internal conductor layer, thereby improving the product qualification rate.

[0015] A preferred solution is that the manufacturing method further includes: step six, repeating steps three to five to complete the manufacturing of multiple internal conductor layers, and each internal conductor layer is connected in series to form a coil.

[0016] It can be seen from this that multiple internal conductor layers can be manufactured as needed.

[0017] In a preferred embodiment, the projection of the through hole at the preset position in step 3 along the thickness direction of the internal conductor layer is located within the projection of the internal conductor layer formed in step 2. The projection of the through hole at the preset position in step 3 along the thickness direction of the internal conductor layer is located within the projection of the electrode groove formed in step 4.

[0018] It can be seen that by limiting the size of the openings and the electrode grooves, the size of the surface depression of the internal conductor layer can be limited, thereby reasonably controlling the DC resistance while avoiding short circuits.

[0019] A preferred solution is that the manufacturing method also includes: step seven, removing the excess insulating dielectric layer outside the coil except the insulating dielectric coating layer to form a coil frame structure consisting of the coil and the insulating dielectric coating layer; step eight, filling magnetic material inside and outside the coil frame structure and pressing it into shape.

[0020] It can be seen that the insulating medium coating layer is formed by removing the redundant insulating medium layer to isolate the magnet and the coil.

[0021] A preferred solution is to form the metal film layer by PVD technology and to form the internal conductor layer by electroplating technology.

[0022] It can be seen that the metal film layer is first formed on the insulating dielectric layer through the PVD technology, which can guide the growth of the copper electrode when the internal conductor layer is electroplated.

[0023] To achieve the third objective, the present invention provides an inductor element manufactured by the above-mentioned method for manufacturing an inductor element. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of an embodiment of an inductor element of the present invention.

[0025] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle.

[0026] Figure 3 It is a three-dimensional diagram of a single-layer internal conductor layer and a connecting conductor in an embodiment of an inductor element of the present invention.

[0027] Figure 4 FIG. 1 is a top view of a single-layer internal conductor layer and a connecting conductor in an embodiment of an inductor element of the present invention.

[0028] Figure 5 It is a bottom view of a single-layer internal conductor layer and a connecting conductor in an embodiment of an inductor element of the present invention.

[0029] Figure 6 It is a schematic diagram of forming a metal film layer on an insulating dielectric layer in an embodiment of the method for manufacturing an inductor element of the present invention.

[0030] Figure 7 It is a schematic diagram of coating a photoresist layer on a metal film layer and opening an electrode groove in an embodiment of a method for manufacturing an inductor element of the present invention.

[0031] Figure 8It is a schematic diagram of forming a first internal conductor layer in an electrode groove and removing a photoresist layer and a metal film layer in an embodiment of a method for manufacturing an inductor element of the present invention.

[0032] Fig. 9 It is a schematic diagram of an embodiment of the method for manufacturing an inductor element of the present invention, in which an insulating dielectric layer is disposed on the first internal conductor layer and a through hole is opened thereon.

[0033] Fig.10 It is a schematic diagram of forming a metal film layer and a photoresist layer on the insulating dielectric layer after the holes are opened, and forming an electrode groove on the photoresist layer in an embodiment of the method for manufacturing an inductor element of the present invention.

[0034] Fig.11 It is a schematic diagram of the method for manufacturing an inductor element in an embodiment of the present invention, after forming an internal conductor layer in an electrode groove, and removing a photoresist layer and a metal film layer.

[0035] Fig.12 It is a schematic diagram of the manufacturing method of the inductor element after each internal conductor layer is completed in the embodiment of the present invention.

[0036] Fig.13 It is a schematic diagram of the coil frame structure in an embodiment of the method for manufacturing an inductor element of the present invention.

[0037] Fig.14 It is a schematic diagram of a method for manufacturing an inductor element according to an embodiment of the present invention, in which magnetic materials are filled inside and outside the coil frame structure and pressed into shape.

[0038] Fig.15 It is a schematic diagram of a complete inductor component product in an embodiment of the method for manufacturing an inductor component of the present invention.

[0039] Fig.16 It is a cross-sectional view of a physical product of a structure in an embodiment of the method for manufacturing an inductor element of the invention.

[0040] Fig.17 It is a cross-sectional view of a physical product of another structure in an embodiment of the method for manufacturing an inductor element of the invention.

[0041] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present invention and its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete and to fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, rather than as limitations.

[0043] The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0044] In the present invention, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediate device, or may not be directly connected to the other devices but have an intermediate device.

[0045] All terms (including technical terms or scientific terms) used in the present invention have the same meanings as those understood by ordinary technicians in the field, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0046] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0047] See also Figures 1 to 5 In this embodiment, the inductor element includes a magnet 1, a coil 2, an insulating dielectric coating 3 and an end electrode 4. The coil 2 is buried in the magnet 1, the end electrode 4 is exposed from the magnet 1 and electrically connected to the coil 2, the insulating dielectric coating 3 is coated outside the coil 2, and the coil 2 and the magnet 1 are electrically insulated by the insulating dielectric coating 3.

[0048] In this embodiment, the coil 2 includes four internal conductor layers arranged along the axial direction of the coil 2 and connected in series. Along the axial direction of the coil 2, the four internal conductor layers are: internal conductor layer 21, internal conductor layer 22, internal conductor layer 23 and internal conductor layer 24. The adjacent internal conductor layer 21 and internal conductor layer 22 are electrically connected via a connecting conductor 201, the adjacent internal conductor layer 22 and internal conductor layer 23 are electrically connected via a connecting conductor 202, and the adjacent internal conductor layer 23 and internal conductor layer 24 are electrically connected via a connecting conductor 203.

[0049] In two adjacent internal conductor layers, a recessed portion is provided on the surface of one of the internal conductor layers away from the corresponding connection conductor, and the recessed portion and the corresponding connection conductor are arranged opposite to each other in the thickness direction of the internal conductor layer. That is, a recessed portion 221 is provided on the surface of the internal conductor layer 22 away from the connection conductor 201, and the recessed portion 221 and the connection conductor 201 are arranged opposite to each other in the thickness direction of the internal conductor layer 22; a recessed portion 231 is provided on the surface of the internal conductor layer 23 away from the connection conductor 202, and the recessed portion 231 and the connection conductor 202 are arranged opposite to each other in the thickness direction of the internal conductor layer 23; a recessed portion 241 is provided on the surface of the internal conductor layer 24 away from the connection conductor 203, and the recessed portion 241 and the connection conductor 203 are arranged opposite to each other in the thickness direction of the internal conductor layer 24.

[0050] The depth of the recessed portion is less than 1 / 3 of the thickness of the internal conductor layer where the recessed portion is located. The cross-sectional area of ​​the recessed portion is less than the cross-sectional area of ​​the connecting conductor corresponding to the recessed portion. That is, the depth of the recessed portion 221 is less than 1 / 3 of the thickness of the internal conductor layer 22 where the recessed portion 221 is located, and the cross-sectional area of ​​the recessed portion 221 is less than the cross-sectional area of ​​the connecting conductor 201 corresponding to the recessed portion 221. The depth A of the recessed portion 231 is less than 1 / 3 of the thickness B of the internal conductor layer 23 where the recessed portion 231 is located, and the cross-sectional area S1 of the recessed portion 231 is less than the cross-sectional area S2 of the connecting conductor 202 corresponding to the recessed portion 231. The depth of the recessed portion 241 is less than 1 / 3 of the thickness of the internal conductor layer 24 where the recessed portion 241 is located, and the cross-sectional area of ​​the recessed portion 241 is less than the cross-sectional area of ​​the connecting conductor 203 corresponding to the recessed portion 241. By controlling the depth and cross-sectional area of ​​the recessed portion, the increase in DC resistance is controlled within 5% while avoiding short circuit of the internal conductor layer, and the inductance of the product is not affected. In this embodiment, the thickness B of the internal conductor layer is equal, and the depth A of each recessed portion is also equal.

[0051] See also Figures 6 to 15 , the method for making the inductor element includes:

[0052] Step 1, see Figure 6 and Figure 7A first metal film layer 61 is formed on the first insulating dielectric layer 51 by PVD technology, a first photoresist layer 71 is disposed on the first metal film layer 61 , and a first electrode groove 81 is formed on the first photoresist layer 71 .

[0053] Step 2, see Figure 8 After forming an internal conductor layer 21 of a preset thickness in the first electrode groove 81 by electroplating technology, the first photoresist layer 71 and the first metal film layer 61 are removed to complete the production of the first internal conductor layer 21.

[0054] Step 3, see Fig. 9 A second insulating medium layer 52 is disposed on the formed internal conductor layer 21 , and after the second insulating medium layer 52 is solidified, a through hole 521 is opened at a preset position of the second insulating medium layer 52 .

[0055] Step 4, see Fig.10 A second metal film layer 62 is formed on the second insulating medium layer 52 after the hole is opened by PVD technology, a second photoresist layer 72 is arranged on the second metal film layer 62, and a second electrode groove 82 is formed on the second photoresist layer 72. The second electrode groove 82 passes through the through hole 521 and extends to the lower internal conductor layer 21 or extends to the second metal film layer 62. The specific extension position can be determined according to the depth of the recessed portion to be formed.

[0056] Step 5, see Fig.11 After forming the internal conductor layer 22 in the second electrode groove 82 formed in step four by electroplating technology, the second photoresist layer 72 and the second metal film layer 62 are removed to complete the production of the second internal conductor layer 22. The upper surface of the second internal conductor layer 22 is recessed downward at a position relative to the through hole 521 to form a groove 220, and a connecting conductor 201 connecting the adjacent first internal conductor layer 21 and second internal conductor layer 22 is formed in the through hole 521.

[0057] Step 6: Repeat steps 3 to 5 to complete the production of the inner conductor layer 23 and the inner conductor layer 24. Fig.12 The internal conductor layer 21 , the internal conductor layer 22 , the internal conductor layer 23 and the internal conductor layer 24 are sequentially connected in series to form the coil 2 .

[0058] Step 7, see Fig.13 , remove the redundant insulating dielectric layers outside the coil 2 except the insulating dielectric coating layer 3, and form a coil frame structure 20 consisting of the coil 2 and the insulating dielectric coating layer 3.

[0059] Step 8, see Fig.14 , magnetic materials are filled inside and outside the coil frame structure 20 and pressed into shape. Fig.14Two coil frame structures 20 are shown.

[0060] Step nine, after the pressed product is subjected to the process steps of dicing, surface treatment, and end electroplating, a Fig.15 The complete inductor component product shown in the figure, the cross-section of the final product is as follows Fig.16 As shown, the number of internal conductor layers in the physical product is five, and in two adjacent internal conductor layers, a recess is provided on the surface of one of the internal conductor layers away from the corresponding connecting conductor. In addition, in other embodiments, after pressing, the structure of the final product is as follows Fig.17 As shown, the surface of the internal conductor layer away from the corresponding connecting conductor is flat and has no recessed portion. This is because before press forming, the volume of the groove on the internal conductor layer is smaller than the volume of the connecting conductor at the corresponding position. Therefore, after press forming, a portion of the connecting conductor completely fills the groove, so that the groove position is no longer recessed.

[0061] In the above steps, the projection of the through hole 521 at the preset position in step 3 along the thickness direction of the internal conductor layer 21 is located within the projection of the internal conductor layer 21 formed in step 2. The projection of the through hole 521 at the preset position in step 3 along the thickness direction of the internal conductor layer 21 is located within the projection of the second electrode groove 82 formed in step 4. By limiting the size of the through hole 521 and the electrode groove, the size of the surface depression of the internal conductor layer is limited, thereby reasonably controlling the DC resistance while avoiding short circuit.

[0062] It can be seen from the above that the relative surface of the internal conductor layer and the corresponding connecting conductor in the thickness direction is lower than the surface of the connecting conductor. In this way, during the pressing process of the magnetic material, space can be reserved for the deformation of the connecting conductor, avoiding the connecting conductor from bulging upward after being stressed and short-circuiting with the adjacent internal conductor layer, thereby improving the product qualification rate.

[0063] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Inductor element, including magnet, coil and end electrodes; The coil is embedded in the magnet, and the end electrode is exposed from the magnet and electrically connected to the coil; The coil comprises a plurality of inner conductor layers arranged along the axial direction of the coil and connected in series, and two adjacent inner conductor layers are electrically connected via a connecting conductor; Features: In two adjacent internal conductor layers, a recessed portion is provided on a surface of one of the internal conductor layers away from the corresponding connection conductor, and the recessed portion and the corresponding connection conductor are arranged opposite to each other in the thickness direction of the internal conductor layer.

2. The inductor element according to claim 1, characterized in that: The depth of the recessed portion is less than 1 / 3 of the thickness of the internal conductor layer where the recessed portion is located.

3. The inductor element according to claim 1 or 2, characterized in that: The cross-sectional area of ​​the recessed portion is smaller than the cross-sectional area of ​​the connecting conductor corresponding to the recessed portion.

4. The inductor element according to claim 1 or 2, characterized in that: The inductor element further includes an insulating dielectric coating layer, the insulating dielectric coating layer is coated outside the coil, and the coil and the magnet are electrically insulated by the insulating dielectric coating layer.

5. A method for manufacturing an inductor element, characterized in that: The production method comprises: Step 1, forming a metal film layer on the insulating dielectric layer, disposing a photoresist layer on the metal film layer, and forming an electrode groove on the photoresist layer; Step 2, after the internal conductor layer is arranged in the electrode groove, the photoresist layer and the metal film layer are removed to complete the production of a single-layer internal conductor layer; Step 3, disposing an insulating dielectric layer on the formed internal conductor layer, and after the insulating dielectric layer is solidified, opening a through hole at a preset position of the insulating dielectric layer; Step 4, forming a metal film layer on the insulating dielectric layer after the opening, disposing a photoresist layer on the metal film layer, and forming an electrode groove on the photoresist layer, wherein the electrode groove passes through the through hole and extends to the inner conductor layer of the lower layer or extends to the metal film layer; Step five, after setting an internal conductor layer in the electrode groove formed in step four, remove the photoresist layer and the metal film layer to complete the production of the next internal conductor layer. The upper surface of the internal conductor layer is recessed downward at a position relative to the through hole, and a connecting conductor connecting two adjacent internal conductor layers is formed in the through hole.

6. The method according to claim 5, characterized in that: The production method further comprises: Step 6, repeating steps 3 to 5 to complete the production of multiple internal conductor layers, wherein each internal conductor layer is connected in series to form a coil.

7. The method according to claim 5, characterized in that: The projection of the through hole at the preset position in the step 3 along the thickness direction of the internal conductor layer is located within the projection of the internal conductor layer formed in the step 2; The projection of the through hole at the preset position in the step three along the thickness direction of the inner conductor layer is located within the projection of the electrode groove formed in the step four.

8. The method according to any one of claims 5 to 7, characterized in that: The production method further comprises: Step 7, removing the redundant insulating dielectric layer outside the coil except the insulating dielectric coating layer, to form a coil frame structure consisting of the coil and the insulating dielectric coating layer; Step eight, filling magnetic material inside and outside the coil frame structure and pressing it into shape.

9. The method according to any one of claims 5 to 7, characterized in that: The metal thin film layer is formed by PVD technology, and the internal conductor layer is formed by electroplating technology.

10. An inductor element manufactured by the method for manufacturing an inductor element according to any one of claims 5 to 9.

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